Blockchain technologies rose to prominence by realising decentralised financial systems and instruments [1]}, [2]}, then branched out into other domains such as supply chain management [3]}. The main draw of blockchains is their ability to securely capture and track the ownership of resources [4]}, e.g., digital cash, real estate, and produce. Smart contracts [1]} have added a second dimension to these use cases by allowing blockchains to control the valid movement of resources.
